public class Car {
    private String brand;
    private Engine engine;
    public Car(String brand,Engine engine){
        this.brand = brand;
        this.engine = engine;
    }
    public String getBrand(){
        return brand;
    }
    public Engine getEngine(){
        return engine;
    }
    public void startCar(){
        System.out.println(brand + "汽车准备启动");
        engine.start();
    }
}